Fatma M. Harb

The Geochemical Correlation of Oils and Source Rock Extracts of Some Wells in the North Western Desert, Egypt

Abstract Many parameters, such as saturates (%), saturates/aromatics ratio, Cmax, C21 + C22/C28 + C29, CPI, pristane/phytane, pristane/n-C17, and pristane + n-C17/phytane + n-C18, obtained from liquid and gas chromatographic analyses are used for geochemical correlation of “10” oil and “4” extracts samples from wells Umbarka-14, Kalabsha-1, Meleiha-4, El Kharita-1, Badr El Din-1,3,4, WD-19, 33 and Abu Gharadig-12 in the North Western Desert. The results revealed that there is a close genetic relationship and remarkable similarities in the origin and maturation for the oils and extracts of the Khatatba and Alam El Bueib source rocks. In contrast, Abu Roash and Bahariya formations show no correlation with the oil. This indicates that Khatatba and Alam El Bueib source rocks seem to act as a source and reservoir for oil generation in the studied wells.

Significance of Aromatic Hydrocarbons in Recognizing Source Depositional Environments and Maturation of Some Egyptian Crude Oils

Abstract The aromatic hydrocarbons were investigated by high resolution of gas chromatography—mass spectrometry of nine crude oil samples from a number of producing wells in the North Western Desert and South Gulf of Suez. A series of molecular indicators of benzothiophenes and dibenzothiophenes were utilized to recognize the significance and their applications in identifying the source depositional environments and maturation of crude oils. The results showed that the studied crude oils were derived from silici-clastic source rocks (Salam-3, El Kharita-1, Zeit Bay-2 and Gemsa-SE oils), and crude oils were derived from carbonate source rocks (Kahraman-1, Tut-1, Meleiha-4, Yasser-1, and E. Esh El Mellaha wells). The maturity parameters 4-MDBT/1-MDBT and 2-+3-MDBT/1-MDBT ratios indicate that the studied crude oils were originated at advanced levels of thermal maturity. Therefore, aromatic hydrocarbons have a powerful way to infer crude oil source rocks depositional environments and maturation.

Source Rock Quality from Oil Biomarkers of the Abu Gharadig Basin in the North Western Desert, Egypt

Four crude oil and core samples were recovered from four oilfields located in Abu Gharadig basin in the North Western Desert, Egypt. The samples were geochemically assessed in order to understand their genetic relationships for determination of source rock quality. API and sulfur contents, n-alkanes, isoprenoids, and Rock Eval pyrolysis were done. The results show that Abu Gharadig oil samples are of marine origin; their source rocks are rich in clay content and were deposited under reducing conditions. Also, these oils have a high maturity level. On the other hand, the source rock samples are reaching to the peak of the oil window for hydrocarbon generation, with a high maturity level and derived from marine organic sources, and show no biodegradation or water washing. This explains much of the chemical and physical properties uniformity observed across crude oil and source rock samples in the basin.

An Organic Geochemical Characterization of Crude Oils from El Hamd and Bakr Oilfields in the Gulf of Suez, Egypt

Abstract Seven crude oil samples were collected from wells of the El Hamd and Bakr oil fields located in the central Gulf of Suez and their chemical composition, API gravity, sulfur content, and asphaltene content were determined. Nickel and vanadium contents were measured using atomic absorption spectroscopy. Saturated paraffinic hydrocarbon fractions were subjected to gas chromatography in order to investigate carbon number distribution. Terpanes and steranes biomarker distributions have been determined using gas chromatography-mass spectroscopy in order to characterize the type of organo-facies, oil classes, depositional environments of the studied crude oils, and to assess the thermal maturity level for oil generation. It has been found that mature oils are generated from marine shales and carbonates are enriched in marine algae with a contribution from terrestrial organic matters.

Bulk Geochemical Characteristics of Crude Oils From Wells in the North Western Desert, Egypt

Abstract Different oil samples were collected from oil fields in the North Western Desert; namely, Meleiha, Razaak, and North Qarun fields. These oils were analyzed geochemically, including sulfur content, American Petroleum Institute (API) gravity, and gas chromatography The results showed that API gravity and sulfur content indicate that the crude oils have high mature level of marine origin. Distribution of n-alkanes (Carbon Preference Index [CPI], pr/ph, and isoprenoide/n-alkanes ratios) reflects that the oil samples originated mainly from marine organic sources deposited in a reducing environment. This indicates that the oil samples under investigation are well correlated with each other in the western part of the North Western Desert.

Source Rocks Evaluation of Sidi Salem-1 Well in the Onshore Nile Delta, Egypt

Abstract Ten core samples representing the subsurface formation of Sidi Salem well No. 1, in the onshore Nile Delta, Egypt. The samples were subjected to comprehensive organic geochemical studies (such as rock-eval pyrolysis, gas chromatograph [GC] and gas chromatography-mass spectrometry [GC-MS]) aiming to evaluate potential source rocks, organic matters types, depositional environments, and maturation. The results revealed that the source rocks in the drilled sections are marginally mature to mature zone and have fair to good potential for generating oil and gas. These rocks are dominated by organic matter derived mainly from mixed organic matters (marine and terrestrial) with contributions from algae and bacteria deposited under anoxic to suboxic saline environments.

Geochemical characteristics of organic matter from Rudeis and Kareem source rocks, Ras Budran oilfield, central Gulf of Suez, Egypt

ABSTRACT The organic matters of Rudeis and Kareem formation from Ras Budran oilfield in the central Gulf of Suez, Egypt, were investigated throughout the study of biomarkers and infrared spectrometric analyses. The results showed that Pr/Ph, Pr/n-C17, and Ph/n-C18 ratios indicated marine source organic matters deposited under reduced condition with a less effect of biodegradation and mature stage of occurrence. The gammacerane index indicated a low-salinity environment of deposition for the initial organic matters existed in the analyzed samples. Steranes distributions show high percentage of C28 steranes and C29 steranes compared with C27 steranes, and low-concentration C27 diasteranes show generally low ratios indicating anoxic carbonate source rocks. The diasteranes/steranes showed generally low ratios indicating most marine carbonate sources. The tricyclic terpane reflects mature organic matters and originated from marine organic sources.

Characterization and correlation of crude oils from some wells in the North Western Desert, Egypt

ABSTRACT Characterization and correlation of crude oils from some wells in the North Western Desert, based on six crude oil samples, were studied by different analytical techniques, including API gravity, sulfur content, nickel and vanadium, bulk compositions and saturated fraction obtained from gas chromatography have been studied. The results show that the crude oils are normal to medium aromatic oils, with high API gravity and high sulfur content. V, Ni, V/Ni and V/(V + Ni) reflecting oils might be sourced from non-clastic source rocks, possibly carbonates, deposited under anoxic-suboxic conditions. Bulk compositions revealing that the crude oils were derived from marine organic sources. While, the paraffins and naphthenes percent indicates that the oils belong to paraffinic to naphthenic oil types, deposited in slightly anoxic to suboxic conditions and contained marine organic matter. Thermal maturity data showed that the oil samples were generated from mature source rocks. This indicates the studied oil samples are well correlated with each other, where they are similar in their oil type maturation and source depositional environments.

Crude oils geochemistry depended specific properties, metalloporphyrins, bulk compositions, and n-alkanes of some Egyptian oils in the Gulf of Suez, Egypt

ABSTRACT The geochemical analyses of Specific gravity (API), sulfur content, nickel and vanadium, porphyrins, bulk compositions, and saturated fraction obtained from gas chromatography have been studied with the aim of throwing more light on the geochemical aspects of the crude oil formation, migration, and maturation. Seven samples were collected from Sudr, October, GS-283, Belayim land, Belayim marine, Kareem, and July oilfields in the Gulf of Suez. These samples are representative for the producing horizon zones of Rudeis and Nuhkul formations of Middle-Lower Miocene age ranging in depths from 1344 to 3558 m. The studied crude oils are classified into heavy and/or intermediate oils. The crude oils have high concentrations of nickel and vanadium contents. Vanadyl porphyrins indicate mature to moderately mature oils. A gross composition reveals marine organic sources. The n-alkanes and isoprenoids in crude oils are derived from marine organic matter, deposited under anoxic/hypersaline to oxic or carbonate environments associated with evaporate and carbonate depositional environment.